Alysia, in her video review, raves about the Nioxin Thickening Gel by Nioxin, specifically targeting those with thin hair. She emphasizes that this gel is a game-changer for individuals seeking volume and definition without the heaviness or crunchiness that other products often bring. Alysia's hair showcases the impressive results of using this gel, with noticeable definition and a full, fluffy appearance. She praises the Nioxin system as a whole but highlights the gel as the key product for thin hair. Overall, Alysia highly recommends giving this gel a try for those looking to enhance their curls and achieve the desired bounce and volume.